The present invention relates to an ultrasonic surgical tool. More particularly, but not exclusively, it relates to a tool for use in a laparoscopic cutting/coagulating system, which is adapted to cut soft material such as flesh or blood vessels.
Such tools are known from our co-pending international application number PCT/GB99/00162. This application describes an apparatus adapted to utilize ultrasonic vibrations in a torsional mode, and this is preferred for the present invention. However, the present invention is not limited to torsional mode vibrations.
The above application describes an apparatus in which the ultrasonic vibrations are transmitted along an elongate waveguide to a distal end provided with cutting and/or coagulating means. A shroud surrounds the waveguide and is isolated from the vibration thereof. The cutting and/or coagulating means comprises a torsionally vibratable element connected to the waveguide in combination with a static non-vibratable element connected to the shroud. This static element may be brought into and out of engagement with the vibratable element by means of an actuating rod extending concentrically within or as part of the shroud. The actuating rod is connected at its proximal end to a scissors grip or other type of operating mechanism.
One disadvantage of such systems lies in the fact that, at the distal end of the apparatus, it comprises a waveguide, surrounded coaxially by an actuating rod which in turn is surrounded coaxially by the shroud. When operating on a patient, bodily fluids at positive pressures may find their way into these concentric spaces, as may some body solids. It is then very difficult to clean the apparatus. It would be advantageous if it were to be possible to detach and discard the shroud and actuating rod, to be replaced by a fresh combination.